Science vs. science: NASA rewriting temperature data?

War of the surface temperature readings:

On the one hand, we have the "HAD-CRUT" record of global temperature, from the UK Meteorological Office's Hadley Research Center for Climate Studies, which shows temperatures decreased since 1998.

The temperature-sensing satellites cataloged by the University of Alambama at Huntsville (UAH) and Remote Sensing Systems (RSS) show a similar decrease.

NASA's Goddard Institute For Space Studies (GISS) data on Global Temperature Land-Ocean Index seems to show accelerating warming since the late 1990s. How can they disagree? Are we getting warmer or cooler?

The NASA data is managed by Dr. Hansen who is Al Gore's chief science advisor, and perhaps the most vociferous global warming advocate in the scientific community. Could they be massaging the data? Indeed they are.

This article at The Register ("Is The Earth Getting Warmer, Or Cooler?"), graphs and compares the global surface temperature records discussed above and shows how NASA is publishing temperature graphs today that differ from their 1999 graphs. NASA lowered temperature readings prior to 1970, making the increase in global temperatures since 1970 seem greater. At the same time, temperatures on the NASA graph since 1970 seem to have become subtly higher, making the recent increases look greater than before.

Obviously, when you see a graph from NASA (GISS), they are not reporting actual temperature readings. They are reporting "real" thermometer readings corrected for... what? (There are a number of reasons for corrections, but these are all subject to interpretation. You are not getting pure, unvarnished data. You are getting massaged data, for better or worse.) For example raw temperature readings from NASA's Arctic sensing stations have been massaged upward by approximately one-half degree in recent years.

Is the time coming when we will view official climate data from the government with the same degree of disbelief that we receive official economic statistics? Perhaps that time has come.

The Register author concludes: "Both of the satellite data sources, as well as Had-Crut, show worldwide temperatures falling below the IPCC estimates. Satellite data shows temperatures near or below the 30 year average - but NASA data has somehow managed to stay on track towards climate Armageddon. You can draw your own conclusions, but I see a pattern that is troublesome. In science, as with any other endeavour, it is always a good idea to have some separation between the people generating the data and the people interpreting it."